This invention relates to a process for incorporating additives into polymers in a colliodal system by emulsifying the system with a compressed fluid.
There have been developed several methods for incorporating additives into polymers, including dissolving the additives in the monomers to be polymerized; introduction of the additives during polymerization; using organic solvents to transport the additives into the polymers; and contacting the polymer under pressure with a compressed fluid having the additive dissolved therein.
However, dissolving additives in monomers can adversely affect subsequent polymerization processes. Polymerization in the presence of additives can be adversely affected if the additives are reactive with the monomers or intermediates or catalysts. Also, if reactive, the additives may be changed into substances that do not serve the purpose the additives were intended to serve. Methods using organic solvents can have multiple processing steps which compromise efficiency and economy and also may require implementation of environmental precautions necessitated by use of often toxic organic solvents.
Therefore, there is still a need for methods of efficiently incorporating additives into polymers.
It is an object of this invention to provide one such method and some products thereof.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. The claims appended hereto are intended to cover all changes and modifications within the spirit and scope thereof.
To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, there has been invented a method for incorporating additives into polymers comprising: (a) forming an aqueous or alcohol-based colloidal system of the polymer; (b) emulsifying the colloidal system with a compressed fluid; and (c) contacting the colloidal polymer with the additive in the presence of the compressed fluid. The colloidal polymer can be contacted with the additive by having the additive in the compressed fluid used for emulsification or by adding the additive to the colloidal system before or after emulsification with the compressed fluid. The invention process can be carried out either as a batch process or as a continuous on-line process.